This invention relates to extruded plastic framing and joining strips useful for holding glazing panes adjacent the frame of an existing prime window and insulating windows including glazing panes assembled with such strips.
In the prior art many types of panel holding strips have been proposed for use in the installation of insulating glazing at a prime window.
These have included strips described in U.S. Pat. Nos. 3,360,893 to Wattelez, 4,069,641 to DeZutter and 3,939,620 to Bero.
Such strips have consisted of elastic rubber mounts as described in U.S. Pat. No. 3,360,893, hinged one piece dual durometer strips as described in U.S. Pat. No. 3,939,620, and two piece interlocking strips as set forth in U.S. Pat. No. 4,069,641.
While such types of strips are useful, their utility is limited in some applications because the strips can hold glazing only of a predetermined thickness for an optimum seal or are otherwise limited in strength so that such strips are not useful for either expansive or heavy glazing panels. Further the utility of many such strips is limited because they are adapted for optimum use only around the perimeter of a single window. Thus, where an array of separate adjacent windows is in a building, as in many commercial and office buildings, a single perimeter strip around each element of the array to hold an insulating pane in correspondence with the window is often impractical. The vertical prime window frame element separating adjacent windows in an array is usually too narrow to hold two adjacent framing strips. Furthermore, even if the vertical prime window frame were wide enough for two single framing elements, additional effort is required to install two strips and the total effect of such an installation may not be esthetically pleasing. In addition, the intrinsic design of such strips renders them unsuitable for coloring or decorative laminating; hence, such strips when installed may not be attractive, or must be painted to match environmental decor.
Further, the manner of installation of such strips may also be limited by a predetermined design, such as headed fasteners in the case of U.S. Pat. No. 3,360,893 or adhesive as in U.S. Pat. No. 4,069,691.